50 years of radiation protection and nuclear power in Switzerland: a brief history

This article presents a short history of research in nuclear physics as well as of 50 years of nuclear power and radiation protection in Switzerland. After the International Conference 'Atoms for Peace' held in 1955 in Geneva the first research reactor was installed in Switzerland. A national environmental radioactivity monitoring programme was started in 1956. Today some 40% of the electricity is produced by nuclear power. In 1986, the southern part of Switzerland was most burdened by radioactive fallout from the Chernobyl Accident. Fortunately, the integral average radiation doses to the population remained below 0.5 milli-Sievert. As in other western countries there was a vigorous debate in Switzerland in the 1980s and 1990s about nuclear power, nuclear safety and the safe storage of radioactive waste

Monitoring of air radioactivity at the Jungfraujoch research station: Test of a new high volume aerosol sampler

The Swiss Federal Office of Public Health (SFOPH) is responsible for the surveillance of environmental radioactivity in Switzerland and for the protection of the public from ionizing and non-ionizing radiation. In order to improve the Swiss radioactivity monitoring network, a new high volume air sampler (DIGITEL DHA-80) was tested in Fribourg and at the Jungfraujoch High Altitude Research Station at 3454 m. The filters are analyzed in the laboratory by a high purity coaxial germanium detector. In the test period natural radio nuclides and traces of ¹³⁷Cs, due to the Chernobyl accident of April 1986, were measured and are in good agreement with values from Germany and Poland. Albeit, the main purpose of this radioactivity monitoring network is to detect rapidly any input of artificial radioactivity, it is also helpful to understand transport of natural radio nuclides in the atmosphere, as for example the cosmogenic ⁷Be and the long-lived radon daughter ²¹⁰Pb. The DIGITEL sampler proved to be sufficiently reliable for aerosol radioactivity monitoring even in extreme meteorological conditions at Jungfraujoch. A detection limit for artificial ¹³⁷Cs of 2 μBq/m³ is obtained

External background radiation in the Fribourg (Switzerland) urban area

Nous sommes constamment exposés à des rayonnements ionisants de multiples sources. La majorité de l'exposition est de provenance naturelle. La composante terrestre et cosmique forme le rayonnement de fond ° externe. Deux types de rayonnement composent la partie terrestre, le rayonnement naturel et artificiel. Le rayonnement artificiel ne contribue que très peu à la dose totale absorbée. Le rayonnement de fond ° externe fut étudié en profondeur dna les prés et champs Suisse, par la Section de la surveillance de la radioactivité, depuis les années 1960. Plus de mille mesures extérieures furent effectuées. Dans les premières années, des mesures de débit de dose, faites avec une chambre à ionisation, étaient comparées avec des mesures de spectrométrie NaI. Depuis le développement de cristaux germanium de très haute pureté, les spectromètres au germanium ont remplacé les NaI dans les mesures de terrains. Dans ce travail, nous souhaitions étudié le bruit de fond ° externe dans un environnement urbain. Pour ce faire, de multiples mesures, à l'extérieur et à l'intérieur, furent effectuées à Fribourg (Suisse) afin d'évaluer le débit de dose moyen et ses variations. Nous souhaitions déterminer l'augmentation de la composante terrestre et la diminution de la composante cosmique autour et dans différents bâtiments. Différents paramètres étaient étudiés dans le choix des sites de mesures. À l'extérieur, nous avons essayé de couvrir au mieux l'espace urbain, en mesurant sur différents types de sol. À Fribourg, différents types de matériaux sont utilisés dans la construction des bâtiments, qui ont une influence directe sur le rayonnement de fond terrestre et cosmique. C'est pourquoi, à l'intérieur, nous avons mesuré le bruit de fond dans des constructions de différents matériaux. De plus, dans la mesure du possible, nous avons mesuré sur différents étages, nous permettant de déterminer l'absorption du rayonnement cosmique par la structure.We are constantly exposed to ionizing radiation of different type. Most of the radiation exposure comes from natural sources. External background ° radiation originates from two different sources, terrestrial and cosmic. Terrestrial radiation originates from two different background, natural and artificial or “man-made” isotopes. The artificial radiation contributes very little to the total absorbed dose. External background ° radiation has been thoroughly studied in the Swiss fields and meadows, by the Environmental Radioactivity Section, since the 1960's. A data base of more than thousand measurement have been performed outdoors. In the early stages, dose rate measurements were performed by an ionisation chamber, and compared to NaI spectrometry measurements. With the development of high purity germanium crystals, HPGe spectrometers have replace the NaI in field measurements. The objective of this work is to systematically survey the external background ° radiation in an urban area. Therefore, various indoor and outdoor measurements were carried out in the Fribourg (Switzerland) urban area, to investigate the average equivalent dose rate and its variation. We want to evaluate the increase of terrestrial contribution and the decrease of cosmic radiation in the vicinity of buildings. Measurements sites were chosen regarding various parameters. For outdoor measurements, we tried to cover most of the urban territory, measuring on different soil types. Many different construction materials have been used for the structure of buildings, influencing both the terrestrial and the cosmic background radiation, when being indoors. Therefore, measurements were carried in buildings made of different materials. Furthermore, measurements were made on many different stories, to evaluate the cosmic absorption by the building structure

Components of total irradiation dose in Switzerland and their ranges

The present knowledge about dose components in Switzerland and their ranges is reviewed. Considerable ranges are found for doses induced by radon decay-products and by cosmic and terrestrial radiation. Yearly doses from radon decay-products show average values between about 1 and 20 mSv in different communities and individual values up to about 150 mSv. The reliability of these average values is, however, limited, because radon concentrations have been measured up to now only in a small number of houses, and because corrections of the raw data are necessary, increasing the uncertainty of the results. Doses from terrestrial and cosmic radiation show locally variable values between about 0.5 and 1.5 mSv per year. These doses are mainly derived from outdoor measurements. Therefore, these results also are only of limited use in possible epidemiological applications

An inter-laboratory comparison of low-level measurements in ground-level aerosol monitoring

After the nuclear reactor accident of Chernobyl, the “Integrated Measurement and Information System (IMIS) for Monitoring the Environmental Radioactivity and Detecting Emissions from Nuclear Plants was implemented in Germany. IMIS is a nationwide comprehensive measuring system which permanently monitors the radioactivity in all important environment media in the whole federal territory. At approximately 40 sites, the activity concentration of radioactive substances is measured in air and precipitations. At least 14 of them are responsible for trace monitoring of radionuclides in the air. The legal bases of IMIS prescribe regular inter-laboratory comparison analyses in cooperation with the Physikalisch-Technische Bundesanstalt (PTB), with the use of reference materials prepared by the Federal Coordinating Laboratories. In order to fulfil this requirement in the field of trace survey measurements in ground-level air, the Federal Office for Radiation Protection (“Bundesamt für Strahlenschutz”, BfS) and the PTB have conducted a comparison with real, dust-loaded reference filters in 2005. The comparison was organized within the framework of a cooperation of trace survey stations from Austria, Germany and Switzerland. The paper describes the preparation of the real, dust-loaded reference filters, the procedure for spiking the filters with the activity standard solution containing ²²Na, ⁸⁸Y, ⁸⁹Sr, ⁹⁰Sr, ¹²⁵Sb, ¹³³Ba, ¹³⁴Cs, and ²⁴¹Am. Some results are discussed and conclusions are given

Radiation exposure to the population of Europe following the Chernobyl accident

On the occasion of the 20th anniversary of the Chernobyl accident an attempt has been made to evaluate the impact of the Chernobyl accident on the global burden of human cancer in Europe. This required the estimation of radiation doses in each of the 40 European countries. Dose estimation was based on the analysis and compilation of data either published in the scientific literature or provided by local experts. Considerable variability has been observed in exposure levels among the European populations. The average individual doses to the thyroid from the intake of ¹³¹I for children aged 1 y were found to vary from ∼0.01 mGy in Portugal up to 750 mGy in Gomel Oblast (Belarus). Thyroid doses to adults were consistently lower than the doses received by young children. The average individual effective doses from external exposure and ingestion of long-lived radiocaesium accrued in the period 1986–2005 varied from ∼0 in Portugal to ∼10 mSv in Gomel Oblast (Belarus) and Bryansk Oblast (Russia). The uncertainties in the dose estimates were subjectively estimated on the basis of the availability and reliability of the radiation data that were used for dose reconstruction in each country